Twilight Sparkle is an Alicorn Princess of Equestria, and one of the more competent ones at that. That said she still tries to shirk her duties, but only so Applejack will give her some attention for once. She is immensely powerful with magic, and has invented many "doo-hickies" that have improved life in Equestria.
Applejack: Best of Friends, back from their Ponyville days, Twilight wishes Applejack would pay her more attention.
Shining Armor: BBBFFs Twilight is extremely protective of her brother, to the point of once punching out his cancer.